Automatic wire dispenser

ABSTRACT

The invention relates to a variable speed, motorized wire dispenser which automatically dispenses wire to a wire using machine under variable wire feed rate conditions. The dispenser includes a support means for a coil of wire, an electric motor to rotate the coil of wire, a motor controller for controlling the operation of the motor, a wire accumulation device having a wire engaging guide mounted at one end of a movable arm and biased to increase the accumulation loop between predetermined limits, and a control potentiometer responsive to the position of the guide to generate a control signal which is transmitted to the controller. The potentiometer is rotated by a drive belt wrapped around a drive sprocket attached to the output shaft of the potentiometer. The belt has one end attached to the frame of the dispenser through a resilient tension spring and has another end attached to the movable arm. A stop member in the form of an adjustable clip mounted on the belt stops movement of the belt over the potentiometer to limit rotation of the potentiometer to a predetermined maximum amount indicative of the highest wire feed rate desired.

BACKGROUND OF THE INVENTION

The present invention relates to automatic wire dispensing machines andmore particularly to an automatic wire dispensing machine that iscapable of dispensing wire from a large spool or coil or the like underdemanding conditions of use that include high rates of wire feed andintermittent and sporadic feed requirements. Such demanding uses aretypical in wire spring forming machines and to a certain extent inautomatic welding machines that use welding wire as a source of themetal forming the weld bead.

Many industrial operations require a substantially continuous supply ofmetal wire. An automatic spring making machine is one type of operation,and an automatic welding machine employing wire to form the weld bead isanother type of operation. For exemplary purposes, the present inventionwill be described in connection with these types of operations, althoughit can be used in other types of operations as well.

In operations requiring a continuous supply of metal wire, the wire canbe provided in a number of forms. It can be wound on a wooden spool orit can be packaged in a drum or loosely in a coil. The wire can bemounted for rotation and dispensation about a vertical or horizontalaxis.

In order to maximize the efficiency of wire feeding operations, it isdesirable to employ supply wire in large quantities; for example, a wirespool weighing up to one thousand (1,000) pounds or more is common. Alarge supply of wire minimizes the number of times that the spool has tobe changed and handled and can provide efficiencies in purchasing thewire in larger bulk quantities.

Large spools of wire present special problems. Because of the inertia ofa full spool, a substantial amount of force is required to start thespool rotating, and when wire usages stops, the inertia of the spoolcauses the spool to continue rotating and continue feeding wire. Whenrelatively thin wire is coiled on a large spool, the problems areespecially acute. A sudden start of the spool can break the wire.Moreover, excess tension in the wire can stretch it to the point of"necking down" to a reduced diameter and correspondingly reduce thediameter of the metal available for the metal forming operation. When aparticular diameter of wire is accurately predetermined, it isundesirable to stretch the wire so that an inconsistently thinner wireis actually available for the operation.

Another problem with requiring a large pulling force to remove wire froma supply spool is that the wire can be wedged between adjacent coils onthe spool and can become gripped tightly enough to resist pulling freeof the spool. Further, the drive mechanism for the metal formingoperation needs to grip the wire tightly in order to overcome theinertia of the spool, and in so doing the teeth of the drive mechanismcan bite into the wire and affect the characteristics of the wire.

Still another problem with the use of a large wire supply spool is thatthe weight of the spool changes markedly as wire is withdrawn from thespool, reducing the weight of a fully loaded spool from one thousand(1,000) pounds to as little as thirty (30) pounds when the spool isempty. This presents a changing inertia force that affects the startingand stopping characteristics of the spool.

A number of machines have been developed to overcome these problems, butnone have been completely successful. Most such machines employ sometype of motorized mechanism for supplying the wire and a mechanicalbrake mechanism for stopping the spool when the wire supply is no longerrequired. Some machines provide tension control devices that areintended to match the feed rate with the utilization rate. Othermachines provide slack wire loops that permit the machine using the wireto make rapid and intermittent use of the wire while providing the wirefeed at a more continuous rate. Such machines often require frequentadjustment to accommodate different sizes of wires, different feedrates, different spool sizes, and changing spool weights and diametersdue to the removal of wire form, the spools. Even with continuouschanges, such machines still are usually not capable of consistent andreliable performance.

It is an object of the present invention to provide an improvedautomatic motorized wire dereeler or dispenser that is simple tooperate, compact, inexpensive, and accommodates a wide range ofoperating conditions without adjustment.

SUMMARY OF THE INVENTION

In accordance with the present invention a variable speed, motorizedwire dispenser for automatically dispensing wire from a coil of wire toa wire using machine under variable wire feed rate conditions comprisesa frame that rotatably supports a coil of wire; an electric motor thatrotates the coil of wire; a motor controller that controls the operationof the electric motor; a wire accumulation mechanism comprising amovable wire that produces an accumulation loop in the wire; and acontrol mechanism that generates a continuously variable electriccontrol signal representative of guide position. The control signal isbeing transmitted to the motor controller so as to produce a change inmotor speed, the control mechanism causing the motor to decrease therate of wire feed as wire supply requirements decrease and increase therate of wire feed as wire supply requirements increase. The controlmechanism comprises a rotary potentiometer having an output shaft, witha drive sprocket being mounted on the output shaft, the potentiometerbeing rotated to change the control signal. The potentiometer is rotatedby a drive belt wrapped at least partially around the drive sprocket,the belt having one end attached to the frame through a resilienttension device and having another end attached to the arm. The endattached to the arm is mounted such that the arm releases tension on thebelt as the arm moves to a position indicative of a smaller accumulationloop, the resilient tension device pulling the belt over thepotentiometer sprocket in such a manner as to increase speed whentension is released in such manner. A stop mechanism or obstruction ismounted on the belt for stopping movement of the belt over thepotentiometer so as to limit the rotation of the potentiometer to apredetermined maximum amount indicative of the highest wire feed ratedesired. Further arm movement in the direction of a decreasing loopproduces no further belt induced potentiometer rotation and consequentlyno further motor speed increase after the belt movement has been stoppedby the stop means.

Other features of the invention include a spring biased feed pulley, alimit switch with a spring biased delay actuator, a small wire dispenserwith a potentiometer with integral bearings, a flat wire dispenser, aloose wire hold-down ring, an improved spring counterbalance for thedancer arm, and an adjustable height pulley support. Other features areapparent from the following description of preferred embodiments of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a wire dispenser of the presentinvention.

FIG. 1A is an exploded perspective view of the wire dispenser of FIG. 1.

FIG. 2 is a perspective view of the improved control mechanism of thewire dispenser of the present invention.

FIG. 3 is a schematic side elevational view of the wire accumulationdevice showing the effect of the use of different sizes of sprockets onthe control potentiometer.

FIG. 4 is a perspective view showing several different sizes of timingpulleys that may be employed in the control potentiometer of the presentinvention.

FIG. 5 is a perspective view showing an adjustable position fixed pulleyarm for the present invention.

FIG. 6 is a perspective view of an improved feed pulley mechanism thatdampens rapid intermittent oscillations in wire supply requirements.

FIG. 7 is a perspective view of a hold-down ring and collar assembly formounting a loose coil of wire on a horizontal wire table.

FIG. 8 is a pictorial view showing an improved limit switch assembly forcontrolling maximum movement of the dancer arm.

FIG. 9 is a perspective view of a light wire dispenser of the presentinvention.

FIG. 10 is a perspective view of a portion of the light wire dispenser,showing the use of an alternative pivotal member for use with somewhatheavier wire.

FIG. 11 is a cross-sectional view of the potentiometer assembly of FIG.9.

FIG. 12 is a schematic view showing a sixty (60) degree potentiometer ofthe type used for the FIG. 9 embodiment.

FIG. 13 is a perspective view showing another embodiment of the presentinvention wherein the wire is flat wire or wire strip.

FIG. 14 is a perspective view showing the flat wire guide roller of FIG.13.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to the drawings, wire dereeler 10 comprises a base 12 havingspaced vertical sides 14 and 16, with a top 18 extending between thesides. The top has an opening 20 therethrough for the drive mechanism. Aone-half (1/2) horse power D.C. drive motor 24 is bolted in the interiorof the housing in slots 26 in vertical sidewall 14. The slots permithorizontal adjustment of the drive motor position. A regenerative motorcontroller 15 of the same type disclosed in U.S. Pat. No. 4,899,945(which is incorporated by reference) is attached to the housing. Thecontroller includes a manually adjustable trim potentiometer 17, whichcontrols the incremental and maximum amount of the controlled powersupply voltage available for the D.C. motor. This makes it possible tovary the incremental and maximum motor speeds over a given range ofmovement of the dancer of the accumulation device of the invention. Thisprovides an important sensitivity adjustment for the product.

A right angle gear mechanism and drive sprocket 28 are attached to theoutput shaft of the drive motor. The drive sprocket 28 drivingly engagesa drive sprocket 30 having an output drive shaft 34 that extends throughopening 20. A table bearing 32 is bolted to the top of the housing overopening 20, such that the drive shaft 34 driven by the drive sprocketsextends through the table bearing. The table bearing can be aconventional automobile wheel bearing. A round table 36 driven by shaft34 is mounted on bolts 38 extending upwardly from the table bearing.Four radial slots 40 extend outwardly in the table from the center atspaced intervals about the table. Spacers 42 properly space the tableabove the table bearing.

When a spool of wire is placed on the table, a central table stem 44comprising a flat base 46 and a vertical axle shaft 48 is mounted on thetop of the table. The stem is attached to the table and bearings bybolts 38 and nuts 50 (FIG. 1). A spool of wire is laid flat on the stemand is rotated by the table. This can be a counter-clockwise orclockwise direction (FIG. 1 orientation), as controlled by a forward andreverse switch on the controller.

Wire is dispensed from the spool through a wire accumulation mechanism52. Wire accumulation mechanism 52 is mounted on a support beam 54extending outwardly from the side of the housing. The support beam is ahollow, rectangular beam. The support beam is extendable by atelescoping beam 56 mounted in the end of beam 54. Set screws 58 holdthe support beam in any desired position. The telescoping mounting beamis provided so that the wire accumulation mechanism does not interferewith wire spools or other containers that may be of an unusually largediameter.

A vertical support arm 60 is attached to the outer end of beam 56 andextends upwardly to an upper end. An outwardly and upwardly inclined arm62 is attached to the upper end of arm 60. Axles 64 and 66 are mountedat the outer and inner ends of arm 62, and reels or pulleys 68, 70 and72 are mounted rotatably on the axles, secured on the axles by collars74 and 76.

A lower pivotable arm or dancer arm 78 extends outwardly from a lowerposition on arm 60, and a single axle 80 extends outwardly from theouter end 102 of lower arm 78. Pulleys or reels 82 and 84 are mounted onthe axle 80 and secured in place by collar 86. The arm 78 is mounted onsupport arm 60 by an axle bolt 110 positioned inward of inner end 100 ofthe arm, with end 100 extending to the left of the axle bolt in FIG. 1orientation.

An important feature of the present invention is an improved wire feedcontrol mechanism 89 that transmits a control signal to the motorcontroller in order to vary the speed of the D.C. motor in accordancewith the amount of wire present on the accumulation device. The wirefeed control mechanism generates a continuously variable electricalcontrol signal representative of the position of lower pivotable arm 78,with the control signal changing gradually as the loop size increasesand decreases. The control signal is transmitted to the regenerativemotor controller and this produces a change in motor speed. The motorspeed decreases as the accumulation increases, and the motor speedincreases as the accumulation loop decreases.

The wire feed control mechanism includes a control potentiometer 90mounted on the inner side of a plate 92 attached at a lower end of arm60. A grooved pulley 94 (FIGS. 1 and 4) is mounted on an output shaft 96of the potentiometer on the opposite side of the plate. A protectorplate 98 is mounted over pulley 94 by appropriate bolts and spacers. Forconvenience, this plate is shown in phantom in FIG. 1 and is removed inFIG. 1A.

A ribbed timing belt 104 is wrapped at least partially around pulley 94and has one end 106 attached to an eye bolt 108, which is in turnattached to arm 78 at a point spaced inward from an axle bolt 110,whereby arm 78 is pivotally mounted to arm 60 for upward rotation. Thisend of the timing belt is attached to the pivotable arm 78 at a pointsuch that upward movement of the arm (indicative of a decreasingaccumulation loop size) releases the tension on the timing belt andcauses this end of the timing belt to move closer to the potentiometer.

The other end 112 of the timing belt is attached by an extension orreturn spring 114 to a bolt 115 on a fixed position member 117 of theframe. When the outer end of arm 78 is pivoted upwardly, the springcauses the timing belt to rotate the potentiometer to speed up themotor. The timing belt passes through a slot 107 in an obstruction plate109, which is in turn attached to plate 92. A clip 105 is fastened tothe timing belt above the obstruction plate and protrudes sufficientlyfar outwardly from the timing belt so that the clip engages obstructionplate 109 as the belt passes downwardly through the opening 107. Clip105 can be two plastic plates fastened together on opposite sides of thetiming belt. The clip limits the movement of the belt over thepotentiometer in a downward direction. The position of the clip can beadjusted to provide any degree of potentiometer rotation before the clipstops the potentiometer from rotating further.

This control mechanism is an important feature of the present invention,because it enhances substantially the adjustability of control availablewith the present invention. With spring 114 pulling the timing belt overthe potentiometer, instead of the arm pulling the belt over thepotentiometer, the arm can be adjusted for maximum speed at almost anydegree of pivotal movement and the arm can continue to move past thatpivotal position without breaking the belt. For example, when arm 78pivots upwardly, spring 114 causes the potentiometer to rotate untilclip 105 stops further rotation. The arm can continue to rotateupwardly, however, and this only produces slack in end 106 of the timingbelt. Thus, if there is a sharp intermittent pull on the wire when themotor is already operating at full speed, the intermittent demand can betaken up by further upward pivotal movement of the arm.

With this construction, it is possible to change the amount of pivotalmovement of the arm necessary to change the motor speed from a stoppedcondition to maximum speed by changing the size of sprocket 94 on thepotentiometer. As shown in FIG. 4, sprocket 94 can be any one of varioussizes, with the sprockets 94a-94e being arranged from the largest numberof teeth or grooves to the smallest number of teeth. When sprocket 94ais mounted on the potentiometer, the degree of rotation of thepotentiometer to achieve maximum motor speed is greater than the degreeof rotation necessary to achieve maximum motor speed when a smallersprocket, such as sprocket 94e, is used. The variation in arm movementbetween minimum and maximum motor speed is represented schematically inFIG. 3. With sprocket 94a mounted on the potentiometer, arm 78 may haveto pivot all the way to position 78a to achieve maximum motor speed. Thedegree of rotation of arm 78 is successively smaller with each smallersprocket until the minimum degree of pivotal movement, represented byarm position 78e, is achieved with sprocket 94e. Sprocket 94e providesmaximum sensitivity in motor speed control with variation in armmovement. In some applications this would be very desirable, while inother applications a larger degree of arm movement might be desirable.

The control mechanism of the present invention makes it possible to usethese different sizes of sprockets to achieve different degrees ofpivotal movement of the arm between minimum and maximum motor speedswhile still permitting the arm to pivot to its maximum position beforecutting off the motor with the limit switch. Even with the smallestsprocket 94e, after the arm has pivoted to position 78e, further pivotalmovement of the arm merely causes the end 106 of the belt to becomeslack, and the belt is not stretched.

With this type of control mechanism, it is also possible to vary thedegree of rotation of the arm between minimum and maximum speeds byusing a different type of potentiometer. As shown in FIG. 12, instead ofusing a conventional three hundred forty (340) degree potentiometer(which provides for a proportionate variation in output signal throughan arc of three hundred forty (340) degrees), a potentiometer having asmaller degree of variation can be employed. In FIG. 12 potentiometer170 is a so-called sixty (60) degree potentiometer, with the variableresistance 172 extending through an arc of only sixty (60) degreesbetween maximum resistance point 172a and minimum resistance point 172b.When a rotating contact 176 is at position 172a, the resistance betweenpoints 174 and 176 is maximum, so the motor speed is minimum. As thecontact slides between point 172a and the other end 172b of the variableresistance, the resistance between terminals 174 and 176 decreases tozero (0). Portion 172c of the rheostat has no resistance, so that afterthe contact passes point 172b, full voltage is applied between terminals174 and 176. Thus, the rheostat or potentiometer rotates between zero(0) and sixty (60) degrees in adjusting the output voltage betweenminimum and maximum. With this type of potentiometer, a much smallerdegree of arm movement is necessary to change the motor speed fromminimum to maximum. By selecting an appropriate size sprocket for thepotentiometer output shaft and by selecting an appropriatepotentiometer, wide variation is possible in the amount of arm movementthat will occur between minimum and maximum motor operating speeds.

This is important, because the objective with any type of wiredispensing apparatus is to have the spool drive motor operating atsubstantially a continuous speed while permitting intermittent use ofwire to be absorbed by the wire accumulation device. While constant feedback between the wire accumulation device and the motor will permitcontinuous adjustment in the motor speed, as the size and diameter ofthe wire coil decreases and for various other conditions, when properlyadjusted, the motor drive should operate at a relatively constant rateof speed as wire is dispensed from the apparatus.

The use of a motor controller with a trim potentiometer 17 in serieswith the control potentiometer further enhances the adjustability of thepresent invention.

An adjustable position threaded stop bolt 116 limits the pivotalmovement of arm 78 in a lower pivotal direction. A limit switch 120actuated by an integral cam arm 122 is mounted to arm 60 in such aposition that a flange 123 on pivoting arm 78 actuates the limit switchif, for some reason, the arm is pivoted upward to its maximum position.The limit switch can then deactuate the wire-using device that isconnected to the dereeler.

The ease with which arm 78 is rotated is determined by the weight of thearm and by adjustment springs attached to the arm. A coil spring 99extends from an eye bolt 98 attached to the lower end of arm 60 to ayoke or collar 101 adjustably mounted on arm 78. This spring urges thearm downwardly and hence makes the arm appear to be heavier than it is.The yoke can be repositioned by loosening lockbolt 103, sliding the yokeon the arm, and then retightening lock bolt 103, in order to change thetension on the spring.

Another coil spring 160 attached to the rear end of the pivotable arm 78extends downwardly and is connected to an adjustable eye bolt 162threaded in a plate 164 fixed to plate 92. By rotating the eye bolt thetension of this spring can be adjusted to lighten the pivotable arm andmake it more responsive to changes in tension in the feed wire.

Wire is routed from the horizontal rotating table to the speed controlmechanism 52 by means of a right angle control rod 126 rotatably mountedon arm 60 by vertical sleeves 128 or 129 (depending on the size of thewire coil) and held in place in the sleeve by collar 130. A horizontalsection of rod 126 has a pair of wire guide fittings 132 and 134attached to the rod by collars 136 and 138. The wire guide fittingscomprise porcelain eyes mounted on mounting plates extending outwardlyfrom the collars. The porcelain eyes serve as a convenient, low frictionguide for directing wire from the horizontal spool upwardly to thepulley mechanism in a smooth curved path that minimizes deflection ofthe wire. Wire 150 coming from the spool extends through the porcelaineyes of wire guides 132 and 134 and then extends upwardly through one orboth of additional wire guides 152 and 154 mounted toward the upper endof arm 60 by brackets 155 and 156. After passing through the wire guide,the wire is then looped around the pulleys and directed to the wireusing equipment. The pulleys may be shifted from axle to axle and thewire may be wound around the pulleys in any desired configuration inorder to position wire at a desired height or dispense wire in a givendirection. One possible way of winding the wire around the pulleys isshown in FIG. 1.

In operation, the swing rod 126 pivots inwardly as wire is dispensedfrom the spool and causes a smooth transition of wire from the reelthrough the porcelain eyes to the pulley mechanism. The porcelain eyesprovide an inexpensive yet effective and efficient low-friction guidemechanism for directing wire from the horizontal spools to thevertically oriented pulleys.

Additional adjustment capabilities of the present invention are shown inFIG. 5. In dispensing wire to a wire using device, it is frequentlydesired to have the wire dispensed from a particular vertical height.While some adjustment in height can be achieved by having the wiredispensed off different pulleys or by having the wire dispensed off thetop or the bottom of the pulley, another means for adjustment of theheight of the pulleys is shown in FIG. 5. In FIG. 5, vertical supportarm 60 has an upwardly and outwardly inclined fixed arm 180 of amodified construction from fixed arm 62. Arm 180 has a hollow outer endand a telescoping portion 182 fits in the outer end of arm 180. A yoke184 having a vertical opening of rectangular cross section 186 is weldedor otherwise fastened to the outer end of arm 182. A vertical supportarm 188 fits in opening 186. An axle 190 extends outwardly from theupper end of support arm 188.

Arm 182 is fastened in any desired position in arm 180 by means of setscrews 192 and an alignment screw 194. Set screws 196 and an alignmentscrew 198 hold arm 188 in a desired position and orientation in yoke184. As shown in FIG. 5, separate set screws 200 hold axles 190 and 202in place in their support arms. The axles can thus be easily removed forreplacement if they should become damaged.

When quick intermittent demands are made on the wire, it is sometimesdesirable to accommodate this without constant pivotal movement of thearm 78. One way of accomplishing this in the present invention is by theuse of pulley 210, shown in FIG. 6. Pulley 210 is mounted on axle 190 bymeans of a rotatable tubular housing 212, which is held axially in placeby collars 214. Arms 216 extend downwardly from spaced locations onhousing 212 on opposite sides of pulley 210. An axle 218 extendingbetween the lower ends of arms 216 rotatably support pulley 210. A rod220 extends rearwardly from collar 214 and is held in a fixed position.A collar 224 is mounted on the outer end of rod 220, and a spring 222extends at an angle between collar 224 and the lower end of one of thearms 216. When wire 150 is rapidly jerked, pulley 210 pivots to theright (FIG. 6 orientation) against the resilient force of spring 222.Spring 122 then pulls the pulley back into its original position. If thepull on wire 150 is anything but a short, intermittent jerk, arm 78pivots upwardly to make an appropriate adjustment in the motor controlspeed. The mounting mechanism for pulley 210 does not provide speedcontrol but it does smooth out intermittent demands for wire.

The rotating horizontal table of the present invention can be used forwire that is packaged in a wide number of configurations. When the wireis coiled loosely, the wire can be held in place by means of thehold-down ring 230 shown in FIG. 7. Hold-down ring 230 comprises anouter ring 232 connected together at a hub by means of spokes 234. Thehub has an opening therethrough that receives a shaft 236 mounted on atable by means of a plate 238. The shaft has a threaded upper end 240. Alarge wing nut clamp 242 is threaded on shaft 240 in order to hold thering firmly against the wire 244. The wing nut can be periodicallytightened to hold the wire coil in place as the wire coil is dispensedfrom the rotating table.

An improvement in a limit switch assembly is shown in FIG. 8. In thisembodiment, a limit switch 250 having an integrally mounted pivoting camarm 252 is mounted on a mounting plate 254. While this cam arm isactuated by the pivotal movement of arm 78, arm 78 does not directlyengage the limit switch. Instead, a delay mechanism 256 is mounted inplate 254 and transfers the force of arm 78 to the limit switch. Delaymechanism 256 comprises a bolt 258 that fits through an opening in plate254 and has threaded nuts 260 on an outer side of the plate and has aresilient spring 262 on the other side of the spring bearing on the headof the bolt. When arm 78 engages the head of bolt 258, the nut firstcompresses spring 262 before the bolt finally engages the limit switchto turn the apparatus off. The delay mechanism thus causes extra springpressure to be exerted against arm 78 before the arm is permitted toengage the limit switch and turn off the apparatus. This extra springforce helps to urge the wire to become untangled if a temporary snagshould cause the full pivotal movement of the pivoting arm. If the extraspring force is sufficient to remove the tangle, the mechanism stays inoperation.

Another embodiment of a wire dispenser in accordance with the presentinvention is shown in FIGS. 9-11. Wire dispenser 260 is particularlydesigned for especially light wire, of the type that might be used inmedical spring applications or the like. With very light and precisewire, it is important not to stretch the wire, so it is especiallycritical to have a very even tension on the wire and a minimum amount ofwire pull to change the speed of the drive motor. With dispenser 260, aslittle as one-quarter (1/4) ounce can be effective in controlling thespeed of the drive mechanism.

As in prior embodiments, dispenser 260 comprises a boxed-shaped frame262 mounted on parallel rails 264. A rotating table 266 is mounted onthe top of the frame, and rods 268 bolted in slots 270 serve as a guidefor loosely coiled wire 272. The wire extends from the coil 274 on thetable through a porcelain eye 276 and then extends through a loop 278 onthe end of a light resilient spring wire 280. Wire 272 then extendsthrough another porcelain eye 282 mounted on a vertical member 284 thatis in turn mounted on a horizontal member 286. A second loop 288 in thewire and a second porcelain eye 290 mounted on member 284 are providedin the event that a double loop of wire is desired.

A second end 292 of wire member 280 is mounted in a collar. 294 that isin turn mounted on the output shaft 296 of a potentiometer 298 by meansof a set screw 300. The potentiometer controls a motor controller asdescribed above. The flex in the wire dampens rapid intermittent demandson the wire dispenser, while the potentiometer provides continuous motorspeed adjustment.

With this construction, it can be seen that a sideways load is placed onthe shaft of potentiometer 298 by wire device 280. Normallypotentiometers are not designed to accommodate a sidewards load. Whileit would be possible to mount the output shaft of the potentiometer in abearing mounted in plate 302, a bearing of this nature would stillprovide too much resistance to rotation of the potentiometer outputshaft. Accordingly, it is significant that the potentiometer be providedwith integral bearings 304 and 306 at opposite ends of the potentiometerhousing and that the shaft 296 be mounted in these bearings. Thisprovides a much lower resistance to rotation of the potentiometer outputshaft and increases the sensitivity of the present apparatus.

As shown in FIG. 10, if the device of FIG. 9 is used for somewhatheavier wire, the metal loop can be replaced by a metal rod 310. The rodhas porcelain eyes 312 and 314 mounted on it instead of loops in therod, but otherwise the operation is similar.

The present invention is adaptable for all kinds of wire, including flatwire or wire strip. As shown in the embodiment 319 of FIG. 13, coils offlat metal strip 320 are stacked one on top of the other on a pallet322, which is in turn placed on a rotating table 324 of the presentinvention. Rotating table is mounted on a base 326 of the type describedpreviously. A telescoping mounting arm 328 extends horizontallyoutwardly from one end of the base. An upwardly extending telescopingsupport arm 330 is mounted on arm 328 by a pivot shaft 332 at the lowerend thereof. A separate telescoping vertical arm 334 can be positionedinside of arm 330, and a U-shaped guide 336 comprising upwardlyextending legs 338 and a base 340 is mounted on the upper end of supportmember 334. The legs on member 336 guide the strip material to a guidepulley mechanism 342, shown in more detail in FIG. 14. Guide pulleymechanism 342 comprises a wide nylon roller 344 rotatably mounted in aU-shaped support bracket 346 by means of an axle 348. The ends 354 ofthe nylon roller are abutted by metal rollers 350 pivotally mounted in abase 352 of the U-shaped support bracket. These rollers 350 arerotatable with the ends 354 of the nylon roller and hold the stripbetween the ends of the nylon roller. The support bracket is mounted tosupport member 330 by means of an angularly movable support bracket 356,which can be adjusted to provide the proper orientation of the rollerfor receiving and dispensing the strip materials.

With this apparatus, wire strip can be fed from coils to appropriatemachinery without bending or kinking the strip material.

As in prior embodiments, the tension on arm 330 can be adjusted by meansof a pair of springs that pull the arm in opposite directions. A spring358 serves to increase the weight or tension of arm 330. This spring isattached to the lower end of arm 330 at a position below its pivotpoint, with one end of the spring being attached to an eye bolt 360 onthe lower end of the arm and the other end of the spring being attachedto the base through a turnbuckle 362. The turnbuckle can be adjusted inorder to vary the tension of the spring. An arm lightening spring 364 isattached to an eye bolt 366 mounted on the frame and an eye bolt 368mounted to arm 330. This spring urges the arm 330 to the right (FIG. 13orientation), thus lightening the tension on the strip caused by arm330. By adjusting the relative tensions of both of these springs andparticularly by adjusting the turnbuckle 362, a proper degree of tensionon the arm to accommodate a particular weight or strip material caneasily be achieved.

The foregoing is merely representative of the preferred embodiments ofthe present invention. Various changes in the construction of theseembodiments may be made without departing from the spirit and scope ofthe present invention, which is defined in the appended claims.

I claim:
 1. A variable speed, motorized wire dispenser for automaticallydispensing wire from a coil of wire to a wire using machine undervariable wire feed rate conditions comprising:a frame including supportmeans for rotatably supporting the wire for dispensing wire to the wireusing machine in a predetermined direction; an electric motor mounted inthe frame so as to rotate the coil of wire; a motor controller thatproduces an electrical output that controls the operation of theelectric motor; wire accumulation means mounted in the frame forproducing an accumulation loop of wire to supply or store wire underrapidly changing demand conditions, the wire accumulation meanscomprising a wire engaging guide movably positioned in the frame suchthat wire extends over the guide in extending from the wire coil to thepredetermined direction, the guide being movable in relation to thepredetermined direction so as to produce an accumulation loop in thewire, the guide being biased to increase the accumulation loop betweenpredetermined limits, the guide being mounted at one end of a movablearm which is movably mounted to the frame at a point removed from theguide; and control means responsive to the position of the guide forgenerating a continuously variable electric control signalrepresentative of guide position, the control signal being transmittedto the motor controller so as to produce a change in motor speed, thecontrol means causing the motor to decrease the rate of wire feed aswire supply requirements decrease and increase the rate of wire feed aswire supply requirements increase, the control means comprising a rotarypotentiometer having an output shaft, with a drive sprocket beingmounted on the output shaft, the potentiometer being rotated to changethe control signal, the potentiometer being rotated by a drive beltwrapped at least partially around the drive sprocket, the belt havingone end attached to the frame through a resilient tension device andhaving another end attached to the arm, the end attached to the armbeing mounted such that the arm releases tension on the belt as the armmoves to a position indicative of a smaller accumulation loop, theresilient tension device pulling the belt over the potentiometersprocket in such a manner as to increase speed when tension is releasedin such manner, stop means being mounted on the belt for stoppingmovement of the belt over the potentiometer so as to limit the rotationof the potentiometer to a predetermined maximum amount indicative of thehighest wire feed rate desired, further arm movement in the direction ofa decreasing loop producing no further belt induced potentiometerrotation and consequently no further motor speed increase after the beltmovement has been stopped by the stop means.
 2. A wire dispenseraccording to claim 1 wherein the belt passes a fixed member as it movesover the potentiometer and the stop means comprises a clip that isreleasably mountable on the belt at a desired location, the clipprotruding outwardly from the belt so as to engage the fixed member andstop further movement of the belt over the potentiometer as the clipmoves adjacent the fixed member.
 3. A wire dispenser according to claim1 wherein the control means further comprises a limit switch fordeactuating the motor after the arm has moved a predetermined maximumamount in decreasing the size of the accumulation loop, the wiredispenser further including a lost motion actuator delay mechanismmounted in the frame separate from the limit switch, the delay mechanismbeing engaged by the movable arm and the delay mechanism in turnengaging the limit switch to shut off the motor only after the delaymechanism has been moved a predetermined amount, the delay mechanismbeing resiliently biased against such movement such that the delaymechanism produces a yieldable force against the movable arm thatresists engagement of the limit switch and urges disengagement of wiretangles.